Vilazodone, 5-(4-[4-(5-cyano-1H-indol-3-yl)butyl]piperazin-1-yl)benzofuran-2-carboxamide, has the following chemical structure:

Vilazodone (HCl salt marketed as VIIBRYD) is an SSRI antidepressant (selective serotonin reuptake inhibitor and a 5 HT1A receptor partial antagonist) developed for the treatment of major depressive disorder. The compound was originally developed by Merck KGaA, Germany, and is now owned by Forest Laboratories Inc, USA.
A synthesis of Vilazodone is described in U.S. Pat. No. 5,532,241.
Certain crystalline forms of Vilazodone hydrochloride, and of Vilazodone dihydrochloride are described in the PCT Publication No. WO2002102794.
Polymorphism, the occurrence of different crystal forms, is a property of some molecules and molecular complexes. A single compound may give rise to a variety of polymorphs having distinct crystal structures and physical properties like melting point, thermal behaviors (e.g., measured by thermogravimetric analysis—“TGA”, or differential scanning calorimetry—“DSC”), powder X-ray diffraction (XRD) pattern, infrared absorption fingerprint, and solid state NMR spectrum. One or more of these techniques may be used to characterize a particular polymorph and to distinguish different polymorphic forms of a compound.
Discovering new polymorphic forms (including new solvates) of a pharmaceutical product can provide materials having, inter alia, desirable processing properties, such as ease of handling, ease of processing, chemical and polymorphic stability upon storage and processing, and ease of purification, or are useful as intermediate crystal forms that facilitate conversion to other polymorphic forms or salts of a pharmaceutical compound. New polymorphic forms and solvates of a pharmaceutically useful compound or salts thereof can also provide opportunities to improve the performance characteristics of a pharmaceutical product. They can also enlarge the repertoire of materials available to a formulation scientist for formulation optimization, for example by providing a product with different properties, e.g., better processing or handling characteristics, improved dissolution profile, or improved shelf-life. Lastly, new polymorphic forms may be prepared with improved reliability and reproducibility compared to other forms, for example in terms of crystallinity or polymorphic purity. For at least these reasons, there is a need for additional polymorphs of Vilazodone and its hydrochloride salt.